Hi Frank,
As my colleague Hongxu mentioned, I do not know if you could integrate the Pulse Secure VPN client directly, but I wonder if you meant the Pulse Secure Access SSL VPN appliance, which you can integrate with Siteminder, and then you may use the Secure Access portal (where you can launch the Pulse VPN client) to access applications protected with Siteminder. As per Juniper documentation:
The Junos Pulse Secure Access (SA) platform supports the Netegrity Siteminder authentication and authorization server along with other common authentication servers. By using a single sign-on SMESSION cookie, it also provides seamless access to all backend applications and servers protected by Siteminder authentication.
Overview
Along with authentication by Siteminder, SA also supports role mapping based on user attributes. In addition to LDAP and RADIUS, you can use Siteminder for retrieving user attributes that can be used in role mapping. When you authenticate SA users using a Netegrity Siteminder policy server, you can enable access to Siteminder protected resources without re-authenticating if authorized with the correct protection level. Additionally, you can re-authenticate users through the SA if they request resources above their current protection level. And you can enable users to sign into the policy server first and then access the SA without re-authenticating.
There is a guide covering this integration, although it is quite old: Here.
You could also request to Juniper if they have updated documentation, although as per the integration steps documented, it may be very similar to perform on current CA SSO/Siteminder releases (and also IVE releases).
I hope it helps.
Albert.